Sand-blast apparatus.



P. SCHROEDER. SAND BLAST APPARATUS.

APPLICATION FILED IAN. I7, I9I3- A 1,301,980 Patented Apr. 29, 1919. Y

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SAND BLAST APPARATUS.

APPLICATION FlLED ]AN.17, 1913- 1,301,809, Patented Apr. 29, 1919.

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P. SCHROEDER.

SAND BLAST APPARATUS.-

' APPLICATION FILED IAN. I7, I9I3. 1 3@} 98% Patented Apr. 29, 1919.

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ATENT @FFIQE.

PAUL SCHROEDER, OF CHICAGO, ILLINOIS, ASSIGNOR TO MOTT SAND BLAST MFG. 00., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SAND-BLAST APPARATUS.

Specification of Letters Patent.

Patented Apr. 29, 1919..

Application filed January 17, 1913. Serial No. 742,557.

To all whom it may concern:

Be it known that I, PAUL SCHROEDER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Sand-Blast Apparatus, of which the following is a specification.

The principal object of my invention is to provide new and improved apparatus for creating a sand blast with compressed air for cleaning or other purposes. Another object of my invention is to provide sand blast apparatus that can be conveniently operated and is at the same time simple and rugged in construction. Another object of my invention is to provide sand blast apparatus with valve control means by which it can be conveniently and readily adapted for use according to may be desired. All these objects and others will be readily understood and appreciated in connection with the accompanying specification and drawings, which illustrate one specific embodiment of my invention. For definition of my invention I refer to the appended claims.

Referring to the drawings- Figure 1 is a front elevation of paratus, the lower tical section.

Fig. 2 is a side elevation, the upper part being shown in vertical section.

Fig. 3 is a detail vertical section taken on the line 3, 3 of Fig. 1, looking in the direction of the arrows.

Fig. 4 is a vertical section taken on the line 4, 4 of Fig. 3, lookingin the direction of the arrows.

Figs. 5, 6, 7 and 8 are sectional'views of my appart being shown in verthe valve designated generally 23, but with the valve member in different operative positions.

The sand chamber comprises a sheet metal cylindrical wall 15 closed above by the concave head 16 and below by the conical hopper portion 17. The concave head 16 has a plug 18 at its center which may be removed for filling the receptacle with sand, in which case the concave head 16 forms a hopper to receive the sand on the outside. The device is supported with the three legs 19.

A compressed air supply pipe is designated 20. Interposed in this pipe is an ordinary valve 21, after passing which the pipe 20 enters the three-way valve casing 22 from various conditions as which two branches extend 27 and 29. The branch 27 goes up to the upper part of the chamber 15 and also connects with a gage 28. The branch 29 extends downwardly and its connections will be described later. The valve member 23 within the casing 22 has three openings designated respectively as 24, 25 and 26. r

In front of the valve 22 is a stationary plate 30 with legends marked thereon to show the positions of the valve. The valve handle is designated 31 and integrally connected thereto is a pointer 32. The different positions of the valve will be described later in connection with the description of the operation of the apparatus.

The pipe 29 that descends from the valve casing 22 is connected at its lower end with a casing 33, which is screwed into the hopper bottom 17 of the sand chamber. This casing 33 has a vertical channel 34 through which sand may pass downwardly to the annular space 38 surrounding the nozzle 36. The pipe 29 connects through the valve 37 with the horizontal passage 35, terminating in the said nozzle '36. Beyond the nozzle 36 is an outlet with a reducer coupling 39' leading to the flexible tubin 40 that carries the mixed air and sand to t e point where they are to be applied.

At the top of the sand conduit 34 is a valve seat or bushing 41 adapted to be closed by the puppet-valve 42. The stem 43 re ciprocates vertically in a vertical channel in the head or casing 33. -The upper end of the stem 43 is bent over, as shown in Fig. 3, and carries the valve member 42. The lower end of the stem 43 is surrounded by a compression coil spring 44 that normally holds the stem 43 down and thus'holds the valve 42 upon'its seat 41.

The hanger 45 depending from the plug 33 has pivoted therein a lever 46 of the first order whose short end engages the lower end of the valve stem 43 by means of the lock nuts 47. The long arm of the lever 46 is connected by the rod 48 to the lever 49 pivoted at 51 on the side of the device. A toothed sector fixed on the side of the device maybe engaged by a pawl on the lever 49 so as to give the valve 42 any desired adjustment of opening.

When the device is out of use both valves 37 and 23 will be closed and valve 23 will have the position shown in Fig. 5. To start the device in operation, the valve 23 will be given a 90 turn counter-clockwise, thus bringing, it. to. the position shown in Fig. 6. This will admit the compressed air through the upwardly branching pipe 27, whence it will enter the chamber 15 above the sand and exert its pressure on top of the sand s well as through the interstices within the same. After this another 90 turn counter-clockwise is given the valve 23, which brings it to the position shown in 7.; this admits. the airboth above, as in the preceding position, and in addition below. This is the normal operating position. Next the; operator opens the valve 37 whiclrpermits the compressed air to blow throughihe nozzle 36- and out through the fiexibletubei iO. The degree of this blast is regulated by the valve 37. Then the operator: manipulates the lever 49 so as to open the valve i2. By gravity and the suction on the sand, thelatter-is forced down through the 1 vertical channel 84 into the annular space38xaround the nozzle 36 and is caught by theai r discharging through the nozzle 36 andcarried'outthrough the tube L0. The quantity of sand in the blast is regulated by means of the'valve 52, the valve 42 being leftvwide open during the operation of the machine.

in order to compensate for the different sizes o-f nozzles which may be used at the end of the tube 40 and to regulate the corresponding flow of sand, a two-way cook 52 is provided in the short pipe leading from theibranch of 'supply pipe 27 to the top of the chamber 15. By adjusting this cock thevolume of air passing through the sand chamberinay be regulated so as to vary the quantityof sand delivered downwardly through the conduit 84 to the annular space around the nozzle 36. In order that the sucti'on. created Within the nipple 53 by the nozzl'e136 may be varied'to discharge through the nipple and into the tube 40, the sand passing downwardly through the conduit 34, the nipple 53 is made adjustable, as shown in Fig. 3, so that it may be screwed inwardly to overlap the end of the nozzle 36 and thereby secure a suction commensurate with the sand which is to be discharged through thetube 40. In order tolock the nipple 53 in any. desired adjustedposition a lock nut 54''-as shown in Fig-. 2'is provided which engages the adjacent end of the coupling projectingfrom the casing 33 and in which the nippleis adjustably supported.

Whenthe nozzle at the end of the tube i0 through which the mixed sand and air isv discharged'upon the work is relatively large, the-cock' '52isl moved so as to permit only a restricted opening from the air supply conduit 27 to the top of the-chamber 15', while the nipple'53" is screwed inwardly so as to overlap! the end} 'of/thenozzle 3 6- and thereby relatively increase the suction and carry into the tube 40 the sand delivered through the conduit 3st around the nozzle 36. The greater the suction the less should be the volume of air admitted abovethe sand in the chamber, inasmuch as the increased suction will result in an increased pull upon the sand, and hence render unnecessary as great a pressure upon the top of the sand. In this manner the proper proportion of sand and air may be maintained regardless of the size of the nozzle which may be used on the discharge end of the tube 40.

It will be observed that intermediate of the mixing chamber 39 and the delivery conduit 40 there is a nipple '55 of less cross section than either the mixing chamber connection or the delivery conduit. This is a feature of importance inasmuch as it protects the conduit 40, which is usually an ordinary rubber hose, from being cut by the sand passing therethrough. The mixed air and sand after passingthrough the reduced nipple 55 expands owingto the larger interior cross section of the delivery conduit 40. In such expansion the air forms an envelop around the mixed sand and air within the conduit 40 so thatthe air alone contacts with the inner surface of the conduit.

\Vhen it is desired to shut the machine off, the sand valve i2 is closed first by means of the lever 49, but the valve 37 is left open. For cleaning purposes after the sand has been applied it is frequently desirable to apply an air blast without sand. To accom plish this the valve 23 may be given another 90 turn to the left, which will bring it to the position shown in Fig, 8, thus shutting off the air supply from the upper part of the sand chamber, but permitting it to dischargethrough the conduit 29'35- i0. Finally, when it is desired to completely shut down the apparatus the valve 23 is given one more 90 turn to the left which takes it from the position shown in Fig. 8 to that shown in Fig. 5.

It will be seen that the-operator stands facing the machine, as it is viewed in Fig. 1, with all the various valves easily within reach. The device is susceptible of any adjustment desired for its work and the air can be applied both for the sand blast and 2. In a device of the class described, a sand chamber with a hopper bottom, a plug connected to said bottom with two vertical passages therethrough and one horizontal passage, one of said vertical passages being for the outlet of sand, a valve stem in the other of said vertical passages, a valve connected with said valve stem to control said sand outlet passage, and means for supplying air under pressure through the horizontal passage across the lower end of the sand outlet passage.

3. In a device of the class described, a sand chamber with a hopper bottom, a plug therein, a sand outlet conduit descending through said plug, a valve at the upper end thereof, a vertical channel through the plug, a valve stem carrying said valve extending through said vertical channel, a fulcrum lug depending from said plug, a lever pivoted thereon and engaging said stem, a hand lever on the side of the sand chamber, and a connecting link from said hand lever to said bottom lever.

4. In a device of the class described, a sand chamber with a hopper bottom, a plug connected with the lower part thereof, said plug having two vertical conduits therethrough and a horizontal conduit, a valve at the top of one vertical conduit, a valve stem through the other vertical conduit connected to said valve, a valve in the horizontal conduit, said horizontal conduit being connected with the lower end of the vertical conduit beneath the valve and enlarged at such point of connection and having a nozzle projecting into the enlarged part so as to form an annular space around the same, an air pressure supply pipe connected to the horizontal conduit beyond the valve therein, and a pipe for mixed air and sand connected to the horizontal conduit beyond the nozzle therein.

5. In a device of the class described, a sand chamber, a casing connected with the lower part thereof, said casing having a horizontal conduit therethrough and a vertical conduit communicating with said chamber and horizontal conduit, a valve at the top end of the vertical conduit to control the passage of sand therethrough, said horizon tal conduit being enlarged at the lower end of said vertical conduit and having an air discharge nozzle projecting into the enlarged part so as to form an annular space around the same, and a nipple engaging the Copies of this patent may be obtained for five cents each, by addressing the discharge end of said horizontal conduit, said nipple being adjustable with respect to the discharge nozzle to vary the annular space around the same.

6. In a device of the character described, the combination with a sand chamber having a discharge conduit leading from the bottom thereof, of a compressed air supply conduit communicating with the upper end of said chamber, a valve in said conduit for controlling the flow of air to the space above the sand in the chamber, an enlarged passage into which said discharge conduit leads, a nozzle through which compressed air is discharged, said nozzle being located in said enlarged passage opposite said discharge conduit, whereby the sand flowing by gravity through said discharge conduit enters said enlarged passage around said nozzle, and a nipple in alinement with said nozzle and adjustable with respect to the same and to the adjacent end of the enlarged passage for varying the annular space around the nozzle and thereby varying the suction on the sand.

7. In apparatus of the class described, a sand chamber, a casing connected with the lower part thereof, said casing having a horizontal conduit therethrough and a vertical conduit communicating with said chamber and horizontal conduit, a valve in said vertical conduit to control the passage of sand therethrough, said valve being maintained wide open during the operation of said apparatus, a compressed air supply conduit communicating with the upper end of said sand chamber, a valve in said conduit for controlling the flow of air to the space above the sand in said chamber, a nozzle in said horizontal conduit opposite the discharge end of said vertical conduit, said horizontal conduit being enlarged around said nozzle, a nipple engaging said horizontal conduit and extending into said enlarged passage, said nipple being adjustable to vary the annular space around said nozzle, and a branch pipe leading from said compressed air supply conduit and communicating with the horizontal conduit in said casing.

In testimony whereof, I have subscribed my name.

PAUL SGHROEDER. Witnesses:

Gno. L. WILKINSON, HENRY A. PARKS.

Gommieaioner of Watenta,

Washington, 11G." 

